Fibrous composition and method for manufacturing same



Patented July 22, 1930 UNITED STATES PATENT OFFICE um. r. s'rnvnnson, or NEWTON, AND HA BBY A. mmon, or nos'ron, uassaonusn'rrs, assronons ro THE monaanson comrm, or LOCKLAND, omo, A coaroaa'rron OF OHIO IIBBOUS COMPOSITION AND METHOD FOR MANUFACTURING SAME Io Drawing.

The process of this invention is concerned with the manufacture of fibrous compositions and comprises a new and novel methodfor securing an intimate combination of'various types of sizes, binders and waterproofing agents with various types of fibers and fibrous tent'of asphalt, and more particularly a higher percentage than has hitherto been feasible. There are today in vogue two processes for the manufacture of asphalt paper; the usual procedure consists in first forming a sheet of paper and then impregnating and coating this with asphalt, exemplified 1n the manufacture of asphalt roofing; the second process, commonly referred to as the Kirschbraun process, which is essentially a sizing process,

. the details of which in its several modifications are set forth in a series of United States patents has as its distinctive feature the addition to the paper mill beater of an emulsion of asphalt in water through the agency of a 0 so-called emulsifying agent, generally a colloidal clay. In contradistinction to the -Kirschbraun method, 'a novel aspect of this invention is the intimate admixture of fiber and asphalt or other binder in the presence of water that is obtained without recourse to the use of an emulsifying agent, with results which are decidedly advantageous from the point ofview of econom and nature of product, as well as of muc eaterrange 40 both in percentages of materia s and variety thereof. In contradistinction to instances where waterproofing substances in liquid or comminuted form have been added to a paper mill heater in which water and stock in usual proportions are circulating, the present proc- Appllcation filed November 1, 1928. Serial 170. 816,611.

ess concerns the forming a preliminary mass of fibers and binder in which the water is not a circulating medium, and in which water is used in relatively small quantities.

We are familiar with the process of Harry G. Fisher, as set forth in his application for Letters Patent Serial No. 314,551, filed October 23, 1928, which process presupposes a complete adhesive coating of fibers with a.

binlder such as asphalt, prior to forming a u p T he resent invention is advantageous over those above noted in economy of operations, extremely wide ranges of materials and proportions, and uniform excellence of product under varying conditions.

By this process not only bitumen, but in like manner, other binders, such as rubber compositions, gums, drying oils, synthetic resins, etc., can be incorporated with paper making fibers; also it affords a convenient and practical method for the sizing of paper with sodium silicate, glue and other waterproofing agents. Mineral fillers can be used, together with the binders and sizes. It will, therefore, be understood that, in describing the process with reference to the manufacture of bitumen fiber combinations, no limita tion to such is implied, and that the process is broadl applicable to a variety of binders and kin s of paper mill materials, as will hereafter be morefully developed.

With reference to its specific application to the incorporation of bitumen and fibers which is an obvious commercial application of my process, some of the many advantages to be recognized are:

1. It is possible hereby to use bitumen having widely different physical properties, ranging from those which are appreciably soft at ordinary temperatures to those which are hard and brittle at such temperatures and do not soften except at quite elevated temperatures;

2. A larger percentage of bitumen can be incorporated with the fiber than is the case with either of the two processes now in use, and previously referred to, it being possible hereby to manufacture a sheet containing as much as 80% of bitumen by weight;

3. It is unnecessary to employ any material such as colloidal clay or organic emulsifying agents;

4. The novel pulp which is the basic product of this invention can be formed into sheets or boards or other shapes by means of ordinary pulp handling equipment.

By bitumen or bituminous m the specification and claims herewith, we include the as phalts, tars and pitches, and the blown oils which are physical equivalents in this art.

Briefly stated, this invention, in one of its aspects, resides in the discovery that when wet sheets of paper or pulp are 1nt1- mately mixed with a fluid or semi-solid binders, a product is obtained which can readily be reduced to a workable pulp on the addition thereto of a further quantity of water and through a mechanical agency, such as a paper mill beater. Various types of mixers can be used for the incorporation of the wet fibers and bitumen, but generally we prefer to work with a kneading machine, of which the well-known Werner-Pfleiderer mixer is an example.

In this particular type of mixer the mixing is not continuous but is by batches, and mixing machines which include extrusion apparatus may be used to provide for continuous delivery of mixed material. \Ve do not regard the method of mixing to be of primary importance.

When using bitumen in a gummy or adhesive condition, it is imperative to add further Water to the fibers before the bitumen has adhesively coated the fibers. \Vith various proportions of bitumen and fiber the mixing temperature should be kept up sufiiciently high that the bitumen does not solidify C0111- pletely.

As directions for the time of mixing and adding further water, it may be stated that no matter what relative proportions of bitumen and fiber be used at the start, the preliminary mixing operation will result first in more or less discontinuous masses of fibrous ,matter together with the bitumen.

With small amounts of fiber, if care is not taken, this condition will soon break down, and the mass will go completely together, due to the mixer action, the action of the binder, and the evaporation of moisture due to the heat of the mixer. As this stage begins to appear, more water should be added, or the fibers may become so coated with the binder that they will resist soaking up the added water, and reduction to a water pulp.

With larger proportions of fiber the mixing is continued until the bitumen and fiber are thoroughly mixed, but discontinued before the moisture content of the fibers has become dissipated to the extent that it is substantially displaced by the binder.

So long as the fibers remain moist, an ap' parently intimate and homogeneous mixture of binders and fiber can be readily broken down to a water pulp on the addition thereto of water in the final stage of mixing.

\Vhile it is the preferred practice to reduce the mass in the WVerner-lfleiderer to aheavy watery pulp by the addition thereto of water immediately following the primary mixing operation, this is not absolutely essential. Substantially the same end result can be obtained by transferring the mass without such intermediate reduction directly to the paper mill beater. An advantage of this preferred practice is that material can be more readily and quickly removed from the mixer in the form of a heavy pulp than when in the state of a wet gummy fibrous mass. The amount of water added to the mixer is not critical.

It is difficult to describe the condition of the material as it comes from the \Verner- Plieiderer operation. Its condition will vary with the ingredients and proportions used. For example, when using asphalt and a fiber furnish consisting chiefly of newsprint or other short-fibered stock, the heavy pulp is at this stage of a mealy consistency and comprises nodulized aggregates of fibers and enmeshed discrete particles of' asphalt; when using a furnish of kraft pulp, the mass comprises fibrous aggregates which are not broken down to the same extent as in the case of shorter fibered stock. The bituminous pulps of this process are apparently quite non-adhesive to the touch, particularly when using the relatively hard asphalts of the specific following examples.

The product of the mixer before the addition of water can be so readily handled, and as lon as it is kept moist is so stable that it can be shipped to distant points and there formed into a pulp or used as an ingredient in a beater. It is hence an article of manufacture that is quite novel and connnercially useful.

On transferring the above partially disintegrated fibrous masses to a beater such as a paper mill heater or any other pulping apparatus, the nodules or lumps are combed out, and in the end, a smooth uniform pulp is obtained, which may be, if desired, passed through one or more refining engines or J ordans. This is the final step or pulping step of our process.

In the form in which the pulp goes to the paper-making machine it can be characterized as an intimate mixture of fibers throughout which the bitumen is distributed. The bitumen is largely suspended as discrete partieles, apparently through the enmeshing action of the highly individualized fibers, said Hill ill!

particles artly the fibers. Some of the fi rs ar e dom etely or partially .coated with a thin, semi-transparent film of bitumen. The material has the characteristics otherwise of a regular fibrous ulp.

The bituminous pulp can be felted by any of the common paper-making ractices. When usin soft bitumens, it may e necessary to coo artificially, the .water in which the pulp is suspended, andto exercise other precautions within the discretion of the skilled operator.

. for the urpose of illustrating the foregoing,

and to escribe the practical operation of the process with respect to specific materials.

E {sample I Asphalt: .A refined asphalt having a ball and ring softening point of 142 F.; a penetration range of:

s at 32-200 ms eo S80. 10 at 77100 .gms. 5 sec. 108 at 1l5.50 gms.- 5 sec.

Fiber: Newsprint.

From the above materials a series of test runs were made, varying the ratio of fiber to asphalt.

Series A: 80% asphalt; 20% fiber B: asphalt; 40% fiber C: 40% asphalt; 60% fiber Each lot of pulp was prepared under identical conditions. First the asphalt was melted in the mixer and brought to a temperature of 175 F. at which it was quite fluid. On adding thereto the wetted newsprint prepared by soaking in water, and then pressing to remove large excess of water, the temperature of the asphalt was quickly lowered to a point at which it was quite viscous, approximately 100 F. Mixing was continuedfor a period of 30 minutes, with steam in the jacket of the mixer to maintain the temperature at or near 100 F. At the end of this period the moisture content of the mixes was approximately 36%. At the conclusion of the mixing period, water was introduced, and the mixer operated for another period of 5 minutes, which was suflicient to partially break up the mass, and reduce it to a condition in which itcould be added directly to the pa er mill better. In the particular beater use in these test runs, it required only 30 minutes with beater water at F. to prepare the pulp for'fabrication into sheets.

The table which follows, shows the efiect of varying the ratio of newsprint fiber to the asphalt herein used.

' Series Thickness g g f gg 335g? A 0 .020 inch 44.11. 13. 73# B O. 017 inch 76# 29. 99# C O. 020 inch 104$]: 41. 40#

Example 71 A The asphalt used in Example I was blown with air at a temperature of 450 F. for differentjperiods of time in order to prepare thereby a series of asphalts of increasingly higher softening points. The pulp, when using these harder asphalts, was made by the same procedure as outlined in Example I, the only change being that higher temperatures were used in the initial mixing operation. In this series, as bel0w,a 40-60 ratio of newsprint to the following asphalts was used:

A-Samo asphalt as in Example I BBall and ring softening point 165 F.

Penetration 3 at 32200 gm.--60 sec. 2 at 77--100 gm.- 5 sec. 20 at 115 50 gm. 5 sec.

C-Ball and rin softening point 196 F.

Penetration at 32-200"gm.60 sec. 0 at 77100 gm. 5 sec. 3 at 115- 50 gm.- 5 see.

. Burstin Series Thickness strengthg A 0.017 76.1 B 0. 020 e5# 0 0. 023 42# Hot calendaring or pressing is advantageous to develop the full strength of the finished sheets.

The nature of the fibrous material has a marked efl'ect on the quality of the finished sheets made from the bituminous pulp of. this invention. In general it can be said that the long and stronger fibers will make a sheet showing higher physical tests than newsprint .Which contains only about 25% of long fiber stock, the remainder being short 'fibered ground wood; When using long fiber stock, it may be found advantageous to partially reduce the fibers by a beating preliminary to mixing with bitumen. A convenient meth- 0d of doing this is to charge the crude (lry fibrous material into the heater mixer, and

by adding .water to it there to permit the at-' trition of the wet fibrous aggregate upon themselves caused by the motion of the mixer blades, to reduce it to moist, finely divided fibers to which the molten bitumen is added. As an alternative procedure, it may in certain instances be found desirable to first prepare a short-fibered bituminous pulp and to subse uently incorporate therewith the longfibere stock.

Example [11 Ratio of asphalt to fiber 70 Asphalt: Gllsonlte 80% Stanollte 70% Ball and ring softening point of mlxture-188 F. Penetration range of mixture 1 at 32-200 gm.-60 sec. 6.6 at 77100 gm 5 sec. 8.6 at 115 gm. 5 sec.

Series A Fiber: Newsprint-5 O% Kraft pulp-50% Series B Fiber: Kraft pulp'-100% In comparable test a sheet (Series A) having a ream weight of 133 pounds showed a bursting strength of 43.8 pounds per square inch as against a sheet from Series B having a ream weight of 138 pounds and a burstmg strength of 69 pounds to the square lnch. The higher test for Series B is attributable to the larger percentage of long-fibered kraft pul irrious optional procedures may be resorted to for the handling of an asphaltized pulp when prepared in accordance with the process herein described. For example, 1t is entirely feasible to prepare a pulp having a maximum content of asphalt and then dilute this with untreated pulp of any kind in the beater operation. Also from one base stock it is thereby possible to prepare a W1de variety of asphaltized sheets, both with res ect to asphalt content and character of her composition. In like manner other materials can be added to the beater, such as inorganlc fillers, wax emulsions, and finely-ground organic materials which preferentially can be introduced at this stage rather than in the initial mixing step.

Another variable which is of some importance in the preparation of this asphaltized pulp is the temperature of the beater water. In general, it will be found that warm beater water is detrimental in the instance of the softer asphalts, and that the proper temperature for beating any given asphalt-containing pulp, is a matter of empirical determination. If, at the temperature of beating, the asphalt is too soft, there may develop a tendency for the initially small and discrete particles to agglomerate and collect between the beater blades. For instance, the asphalt used in Example I should preferably be beaten at or below F., while in the case of the harder asphalts used in Examples II and III it may be found advantageous to heat the water. It is not possible to'lay down any fixed principle for this variable factor, as different asphalts of substantially the same ball and ring softening point do not behave exactly the same, owing to other inherent and important qualities, such as their relative extensibility and penetration at any given temperature; also the percentage and character of pulp is a factor in this consideration.

While the process has been specifically described in reference to the preparation of an asphaltic or bituminous ulp no limitation to the use of bitumen is t ereby intended or implied. In place of bitumen, various materials can be handled to advantage and to secure a new and novel result. For exam le, we have successfully replaced the asphalt in part or whole by waxes and gums, such as parafiin and kauri. Also we have used rubber in combination with various fluxes, such as ine oil, and vegetable and animal oil pitches.

artially oxidized drying oils, such as boiled linseed, constitute another class of materials adaptable to this process. Whereas these binders and sizing agents are not used in an emulsified state, the fact that they may not be emulsifiable is not a limitation in the present instance.

It is not necessary that the material to be mixed with the fibers be adhesive and extensible enough to distribute the fiber. It is found that using a liquid, or semi-solid, binder, preferably in the presence of heat, which is capable of coating the fiber, and mixing it with wet fibrous material, which mixing is carried on until the ingredients are about to go together and seem to form a uniform looking mass in the mixing machine, and then adding a further amount of water and proceeding with the mixing, will result in a mass which can be pulped in a beater and thereafter treated in almost any manner in which pulp can be treated.

It is possible to practice our process by the contlnuous adding of limited amounts of water during the mixing stage instead of letting the mass go through the two phases of going together, and then disassociating into a nodulized fibrous pulp. The same end result is sought as has been described, but the association and lumping takes place in amounts less than the whole batch, and the time of treating is longer and fiber length is reduced, and the product is not so uniform.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. The process of preparing a fibrous pulp containing asphalt comprising the steps of reducing an asphalt to a molten condition by heat, and adding thereto a redetermined weight of wet fibrous materia mixing said materials under conditions to disintegrate and disperse the fibers, and thereafter adding to the mixer while in action, an additional amount of water suificient to partially bieaik up the adhesive mass of fibers and asp a t.

2. The process of preparing a fibrous pulp containing asphalt comprising the steps of reducin an asphalt to a viscous condition and ad ing thereto a predetermined weight of wet paper, mixing said materials in the preferred atla'ype of mixer as described, until a substanti y homogeneous condition is reached, and thereafter adding to the mixer while in action, an additional amount of water suflicient to partially break up the adhe sive mass of fibers and asphalt.

3. The process of preparing a. fibrous pulp containing asphalt comprising the steps of reducing au asphalt to a viscous condition and adding thereto a predetermined weight of -containing asphalt comprising the steps of reducing an asphaltic material by heat to a viscous, semi-liquid condition, and adding thereto a fibrous pulp saturated with water,

mixing said materials in the preferred type of mixer as described, until a substantially homogeneous condition is reached, thereafter adding to the mixer while still in action, an amount of water equal to at least 50% by weight of the mixer charge and then transferring the mass when sufliciently broken down to a beater engine wherein the pulping operation is completed.

5. The process of preparing a fibrous pulp containing upwards to 80% of an asphaltic material comprising the steps of reducing an asphalt to a viscous condition and ad ing thereto a predetermined weight of wet aper, mixing said materials in the preferre ty e of mixer as described, until a substantial y homogeneous conditions is reached, and thereafter adding to the mixer while in action, an additional amount of water sufiicient to partially break up the adhesive mass of fibers and asphalt.

6. The process of preparing a fibrous pulp containing upwards to 80% of an asphaltic material comprising the steps of reducing an asphaltic material by heat to a viscous, semiliquid condition and adding thereto a fibrous pulp saturated with water, mixin said materials in the preferred type of mixer as described, until a substantially homogeneous condition is reached, thereafter adding to the .mixer while still in action, an amount of water equal to at least 50% by weight of the mixer charge and then transferring the mass when sufliciently broken down to a heater engine wherein the pulping operation is completed. 7'. The process of preparing a fibrous pulp containing asphalt comprising the steps of reducing an asphaltic material by heat to a viscous, semi-liquid condition and adding thereto a fibrous pulp saturated with water,

mixing said materials in the preferred type of mixer as described, until a substantially which consists in mechanical homogeneous condition is reached, thereafter adding to the mixer while still in action, an

amount of water equal to at least 50% by.

wei ht of the mixer charge and then transferrmg the mass when reduced to a nodulized fibrous condition, to a heater engine wherein the asphaltic pulp is diluted by the addition thereto of fresh, untreated pul 8.- A fibrous product consisting of wetted fibers intimately associated with a heat plastic binder, in which the fibers have the characteristic of substantially immediately absorbing more water.

9. A fibrous roduct consistin of wetted fibers intimate yassociated wit a coating substance in which the fibers have the characteristic of immediately absorbing more water.

10. The process of preparing a bituminous fibrous combination comprising the steps of mechanically distributing said bituminous material when a non-solid throughout a mass of wetted fibers without the use of an emulsiging agent, the water present being insu cient to act as a circulatin medium, diluting the mixture and therea ter forming a web therefrom on a paper machine.

11. The process of preparing a waterproof fibrous combination comprising the steps ofmechanically distributing a heat plastic waterproof material when a non-solid throughout a mass of wetted fibers without the use of an emulsifying agent, the water present being insufiicient to act as a circulating medium, and thereafter forming a pulp from the mixture and forming a Web therefrom on a paper machine.

12. The process of preparing a waterproof fibrous combination comprising the steps of mechanically distributing a heat plasticwaterproof material throughout a mass of wetted fibers without a the use of an emulsifying agent in the presence of heat, the water present being insufiisient to act as a circulating medium, and thereafter forming a pulp from the mixture and forming a web therefrom on a paper machine.

13. The process of preparin a pulp of which the initial step consists in b matter and a desired heat plastic while hot and plastic, without sealing the fibers by a complete coating of the same in the presence of insufiicient water to act as a circulating medium.

ringing together by a mechanical mixing, wet fibrous when a non-solid gether a mass of fibrous material in the form of aggregates which require disintegration in order to form pulpable fibers with a binding agent, which is in a state of flow during the working, to a condition of uniformity, and then incorporating the resultant mass with sufficient water to form a pulp.

16. That process of makin a fibrous pul which consists in the steps 0? mixing wette fibrous material in the presence of a water immiscible binder in an adhesive and extensible condition to a substantiall uniform mass without makin the fibers dry, but in which there is insu cient water to act as a circulating medium, and thereafter incorporating further Water into the mass accompanied by mechanical treatment to the extent of forming a pulp.

17. The process of preparing a fibrous material for pulping comprising the steps of mixing the wetted fibrous material in the presence of a binding material which is in an adhesive and extensible condition to a substantially uniform mass without making the fibers dry, and with insufiicient water to form a pulp, thereafter adding further water and continuing the mixing through mechanical treatment.

18. The process of preparing a bituminous fibrous combination comprising the steps of mechanically distributing said bituminous material when in an adhesive and extensible state throughout a mass of wetted fibers, whereby the action of the binder on the fibers isto separate them due to the action thereon of the binder, diluting the same with water and forming a web therefrom. on a paper machine.

19. That process of making a fibrous-pulp which consists in the mastication of a mass of wetted pulp stock and a bituminous binder by kneading in a heated compartment while maintaining therein sufiicient water to prevent the adhesive coating and agglomeration of the individual fibers, but insufiicient to prevent the kneading operation, and thereafter reducing the resulting material to a Watery pulp by further addition of water.

20. That process of making a fibrous pulp which consists in the mastication of a mass of wetted pulp stock and a bituminous binder by kneading in a heated compartment while mixing the wetted material in the presence of hot bitumen without making the fibers dry and in the absence of sufiicient water to act as a circulating medium, thereafter adding further water and continuing the mixing through mechanical treatment.

22. The process of pulping a fibrous material comprising the ste s of mechanically mixing the wetted material in the presence of hot bitumen without making the fibers dry and in the absence of sufiicient water to act as a circulating medium, thereafter adding further water and continuing the mixing through mechanical treatment, and finally forlming a paper machine pulp of the materia 23. The process of pulping a fibrous material comprising the steps of mechanically mixing in the presence of heat the material while wet and a binding material while in state of flow, with the result of producing a mass only partially moist, and then applying further, mechanical workin in the presence of additional water, and ii nally forming a pulp in the usual way.

24. The process of pulping a fibrous material comprising the steps of mechanically mixing in the presence of heat the material while Wet and a heat plastic material while in state of flow, with the result of producing a mass only partially moist, and then applying further mechanical working in the presence of additional water, and finally forming a pulp in the usual way.

EARL P. STEVENSON. HARRY A. BURON.

maintaining therein sufiicient water to prevent the adhesive coating and agglomeration of the individual fibers, but insufiicient to prevent the kneading operation, and thereafter reducin the resultin material to a watery pulp y further addition of water, said water being added in two stages, the first bein during an additional mixing treatment similar to that above described, and the second being during the usual pulp forming operations in a beater.

21. The process of pulping a fibrous material comprising the steps of mechanically DISCLAIMER 1,771,150.Ea rl P; Stevenson, Newton, and Hairy A. Baron, Boston, Mass.- Fnmove COMPOSITION AND Mn'rnon FOR MANUFACTURING SAME. Patent dated July 22', 1930. Dlsclaimer filed July 9, 1932, by the assignee, The Richardson Company.

Hereby disclaims claini 15 of the said patent, except where the pulpable fibers,

previous to the final dispersion step, are in a conditlon to readily take up water without agitation.

[Qflicial Gazette August 2,1981%] 

